KR100768728B1 - Control of switched reluctance machines - Google Patents

Abstract

A polyphase switched reluctance machine controlled by a control system using sensorless position detection. The controller is robust and reliable and operates over the entire speed range of the machine. In the chopping mode. diagnostic pulses of predetermined flux linkage are injected into an idle phase. In the single-pulse mode, position prediction is done using an active phase. A method of starting the machine uses diagnostic pulses in two phases to provide a unique value for position, allowing the drive to start or re-start under full torque. <IMAGE>

Description

Switched magnetoresistive machine and its control method {CONTROL OF SWITCHED RELUCTANCE MACHINES}

1 illustrates the basic elements of a switched magnetoresistive driver system.

2 is a schematic view of a rotor pole approaching the stator pole.

3 shows a conventional switching circuit in a power converter controlling the excitation of the phase windings of the machine of FIG.

4A and 4B show typical current waveforms of a switched magnetoresistive driver operating in chopping and single pulse modes, respectively.

5 is a schematic diagram of a switched magnetoresistive driver system according to the present invention.

6 shows an ideal inductance profile, excitation area and diagnostic area of a machine operating in a low speed mode according to the invention.

7 shows an ideal inductance profile and possible reference angle positions for a machine operating in a high speed mode according to the invention.

8 shows a position determined during startup according to the invention.

9 is a flow chart in accordance with the operation of the present invention.

<Brief description of symbols for the main parts of the drawings>

42: magnetoresistance machine

44: rotor

46: stator

48: phase winding

50: switch device

56: current sensing element

FIELD OF THE INVENTION The present invention relates to the control of a switched magnetoresistive machine, and more particularly to a switched magnetoresistive machine operating without a sensor for measuring rotor position.

In general, a magnetoresistive machine is an electric machine whose torque is generated by moving the movable portion to a position where the magnetic resistance of the magnetic circuit is at a minimum, i.e., the inductance of the excitation winding is at its maximum. Some types of magnetoresistive machines are equipped with circuitry for detecting the angular position of the rotor and for energizing the phase windings as a function of the rotor position. This is commonly known as switched magnetoresistive machines and can be used as a motor (motor) or as a generator. The characteristics of such switched magneto-resistive machines are known, for example, The Characteristics, Design and Application of Switched Reluctance by Stephenson and Blake at Nurimberg's PCIM'93, June 21-24, 1993. motors and drives , the disclosure of which is incorporated herein by reference. The cited document discloses in some detail the features of a switched magnetoresistive machine which together produce a cyclically varying inductance which is characteristic of the phase windings.

1 illustrates the basic elements of a conventional switched magnetoresistive drive system. The input DC power supply 11 can be a battery or a rectified and filtered AC power supply, which can be fixed or variable in size. In some known drivers, this power supply 11 comprises a resonant circuit which generates a rapidly varying DC voltage between a zero value and a predetermined value to allow zero voltage switching of the voltage switch. The DC voltage generated by the power supply 11 is switched across the phase winding 16 of the motor 12 by the voltage converter 13 under the control of the electronic control unit 14. This switching must be accurately synchronized to the rotational angle of the rotor for proper operation of the driver. The rotor position detector 15 is generally adapted to provide a signal indicative of the angular position of the rotor. The output of this rotor position detector 15 can be used to generate a speed feedback signal.

The rotor position detector 15 may take many forms, for example, may be in the form of hardware schematically shown in FIG. In some systems, the rotor position detector 15 has a rotor position transducer that provides an output signal that changes state each time the rotor rotates to the position where the device requires a different switching structure of the device in the voltage converter 13. can do. In other systems, the rotor position detector may be a software algorithm that calculates or measures position from other monitored factors of the drive system. These systems are sometimes referred to as "sensorless position detection systems" because they do not use physical transducers associated with the rotor to measure the position. As is known in the art, many different methods have been proposed by the request for reliable sensorless systems. Some of these are described below.

The excitation of the phase windings in a switched magnetoresistance machine depends on the detection of the angular position of the rotor with respect to the stator. This will be explained with reference to FIGS. 2 and 3, which shows the switching of a magnetoresistive machine operating as a motor. 2 shows the rotor 24 with the rotor pole 20 approaching the stator pole 21 of the stator 25 according to the arrow 22. As shown in FIGS. 2 and 3, the portion 23 of the complete phase winding 16 is wound around the stator pole 21. When the portion 23 of the phase winding 16 around the stator poles 21 is excited, a force will be applied to the rotor to align the rotor poles 20 with the stator poles 21. FIG. 3 shows a typical switching circuit in the power converter 13 that includes the part 23 around the stator pole 21 to control the excitation of the phase winding 16. When the switches 31 and 32 are closed, the phase windings are coupled to a DC power source to supply power. Lamination forms, winding topologies, and many other structures of switching circuits are known in the art, some of which have been discussed in the above-mentioned Stefanson and Blake literature. When the phase windings of the switched magnetoresistive machine are excited in the manner described above, the magnetic field set by the magnetic flux in the magnetic circuit generates an external force, which aligns the rotor poles with the stator poles as described above.

In general, the phase windings are excited to affect the rotation of the rotor as follows. At the first angular position of the rotor (“turn on angle” Θ _ON ), the controller 14 provides a switching signal to turn on both switching elements 31, 32. When the switching elements 31 and 32 are turned on, the phase windings are coupled to the DC bus so that increasing magnetic flux is set in the machine. This magnetic flux generates a magnetic field in the air gap that causes the motor to generate torque on the rotor poles. The magnetic flux in the machine is maintained by the magnetic force (mmf) provided by the current from the DC power supply via the switches 31 and 32 and the phase windings 16. Current feedback is conventionally employed and the magnitude of the phase current is controlled by the chopping of the current by quickly switching on and off the switching elements 31 and / or 32. 4A shows a typical current waveform in chopping mode of operation in which current is chopped between two fixed levels. In the motoring operation, the turn-on angle Θ _ON is sometimes selected as the rotor position where the center line of the interpole space on the rotor is aligned with the center line of the stator pole. But it can be any other angle.

In many systems, the phase windings maintain a connection to the DC bus (or intermittently if chopping is used) until the rotor rotates to reach the so-called "freewheeling angle" Θ _FW . When the rotor reaches an angular position corresponding to the freewheel angle (e.g., the position shown in Figure 2), one of the switching, e.g. switch 31, is turned off. In conclusion, the current flowing through the phase winding will continue to flow, either through only one of the switches (in this example switch 32) or through only one of the diodes 33/34 (in this example diode 34). will be. During the freewheel period, the voltage drop across the phase windings is small and the magnetic flux remains substantially constant. The circuit remains in this freewheel until the rotor rotates at an angular position known as the "turn-off angle" Θ _OFF (eg, where the center line of the rotor poles aligns with the center line of the stator poles). . When the rotor reaches the turn off angle, the switches 31 and 32 are both turned off and the current in the phase winding 23 begins to flow through the diodes 33 and 34. The diodes 33 and 34 then reversely apply the DC voltage from the DC bus, reducing the magnetic flux (ie, phase current) in the machine. It is known in the art to use other switching angles and other current control configurations.

As the speed of the machine rises, the time for raising the current to the chopping level becomes short, and the driver normally operates in the "single-pulse" operating mode. In this mode, the turn on, freewheel and turn off angles are selected as a function of speed and load torque, for example. Some systems do not use the freewheel angular period. That is, the switches 31 and 32 are turned on and off at the same time. 4B shows a typical single pulse current waveform with a freewheel angle of zero. It is known that the values of the turn-on, freewheel and turn-off angles can be predefined and stored in some suitable format for recall, calculation or derivation in real time as required by the control system.

It will be realized that the sensorless position detection system can provide the rotor position signal in chopping and single pulse operating modes if the full capability of the switched magnetoresistive machine is realized. Although many sensorless systems have been proposed, they are likely to be limited to one mode of operation or to severely limit the operation of the system. One proposed method using diagnostic pulses in an ideal phase is described in Proc PEVD Conf. IEE Pub'n NO 324, pp 249-252 is disclosed in A new sensorless position detector for SR drives by Mvungi et al. This method was successful in chopping mode, where the rise and fall times of current were relatively short compared to the entire excitation cycle. This citation acknowledges that other methods are required for high speed (eg, single pulse) operation.

The method for high speed operation is illustrated in EP-A-0573198 (by Ray) which discloses a method of measuring magnetic flux and current prior to the prediction of the rotor position. Many other sensorless position detection systems are reviewed by Ray et al. In September 1993, Sensorless method determining the rotor position of switched reluctance motors , Proc EPE'93 Conference Vol 6, pp 7-13, UK Brighton. And that none of these methods totally satisfy the operation for all operating ranges.

The present invention relates to a multiphase switched magnetoresistive machine controlled by a control system for detecting position without a detector, and to determine the rotor position in a multiphase switched magnetoresistive machine having a rotor, stator and an excitable winding having one or more phases. Its purpose is to provide a method. According to the present invention, it is possible to provide a switched magnetoresistive machine which is stable and reliable and operates over the entire speed range of the machine.

According to the present invention, a method is provided for determining rotor position in a multiphase switched magnetoresistive machine having a rotor, a stator and an excitable winding having one or more phases. The method includes applying a first diagnostic pulse of a predetermined linkage flux to a phase winding of one of the two or more excitable phase windings; Applying a second diagnostic pulse of a predetermined linkage flux to another of the phase windings in which the two or more phases are excitable substantially simultaneously with the application of the first diagnostic pulse; Determining possible first rotor positions from the characteristic detected from the first diagnostic pulse; Determining possible second rotor positions from the characteristic detected from the second diagnostic pulse; Comparing the possible first rotor position with the second rotor position to resolve the ambiguity of the rotor position.

The present invention takes advantage of the fact that the ambiguity of whether a point in a phase inductance cycle is closer to one end of the cycle or closer to the other end can be solved by comparing these pairs of diagnostic pulses in individual phases. Is useful. There will only be one point in this cycle that the characteristics detected from both diagnostic pulses coincide.

The detected characteristic is preferably the current in the winding. Possible values of the rotor position can be stored in a look-up table. Since the symmetry relationship exists between the motoring mode and the generating mode of operation in a symmetrical machine, in its magnetic properties only one set of values needs to be stored to satisfy both modes of operation. . Relief of protection is achieved by comparing the indicated rotor positions and selecting one rotor position which is common in the detected properties.

The invention can be used when the rotor position is missed at start up of the machine or while being driven. In the latter case (i.e., if the rotor position is missed during driving), it is desirable to allow the attenuation of the current or magnetic flux to be substantially zero in order to avoid error calculation of the position.

The invention also relates to a rotor, a stator, a plurality of excitable windings, switch means operable to excite the plurality of phases, position detection means for inducing the position of the rotor relative to the stator and the rotor position. A switched magnetoresistive driver comprising means for driving said switch means, said position detecting means comprising: means for applying a first diagnostic pulse of a predetermined linkage flux to one of said plurality of phases; Means for applying a second diagnostic pulse of a predetermined linkage flux to another one of said plurality of phases substantially simultaneously with the application of said first diagnostic pulse; Means for determining a possible first rotor position from the characteristic of the first diagnostic pulse and determining a possible second rotor position from the characteristic of the second diagnostic pulse; And means for resolving ambiguity of the rotor position by analyzing the first and second rotor positions.

The machine preferably comprises means for operating the switch means in accordance with the decrypted rotor position. The present invention can be realized in a number of ways. Some of these will be described through embodiments with reference to the accompanying drawings.

In FIG. 5, the switched magnetoresistive machine system includes a magnetoresistive machine 42 having a rotor 44 mounted to rotate in the stator 46. This stator has two or more (possibly three) phase windings 48 which are individually excitable as mentioned above.

A conventional switch device 50 is connected to each phase winding. For the sake of clarity, only one winding is shown in FIG. 5, which is schematically shown in the switch arrangement. This switch device controls the application of the DC supply voltage V from the power supply 52.

This switch device is an application specific integrated circuit (ASIC) programmed to receive current information from each of a pair of windings 48 by a current sensing element 56, such as a Hall-effect element. Is controlled by a controller 54 having This ASIC is conceptually shown as being connected to an analog / digital converter 58 and a look-up table memory 60. In practice, the system can use one A / D channel multiplexed between two current signals, use two dedicated channels, or use each current transducer. Such systems are known. Current transducers can also conveniently provide signals useful for other current monitoring functions in the system.

The A / D converter 58 is configured to digitize the signal indicative of the current value sensed by the element 56, but the look-up table is accessed by the ASIC to convert the detected current value into the rotor angle. The value of the rotor angle for a given current varies from machine to machine, but should be common for the currents detected in both phases based on the assumption that the phase structure is nearly similar. However, separate look-up tables for each phase can be used when the phase characteristics become significantly different.

The ASIC is programmed to drive the low speed (chopping) control mode and the high speed (single pulse) control mode as mentioned above, the starting method of which is described below. It will be appreciated that the control function of the ASIC is based on programmed software. Thus, its operation is partially initiated by the flowchart of FIG. 9 (described below). When the machine is running at low speeds, the rotor position can be determined by applying a diagnostic pulse of the intersecting flux of a predetermined magnitude to the inactive (resting) phase winding. This linkage flux becomes the time integration function for the electromotive force emf applied to the winding, i.e.

Where Ψ is the linkage flux of the coil. V is the effective supply voltage (less than any voltage drop in voltage converter 50), i is the coil current, and R is the coil resistance. The current is detected by the current sensing element 56 in each phase winding in response to the applied flux pulses. Integrating (V-iR) can be performed in an ASIC according to known methods. Thus, a voltage is applied from the power supply 52 to monitor the increase value of the integral, and when the linkage flux reaches a predetermined value, a diagnostic pulse is generated by removing the voltage. By knowing the linkage flux and current values, the rotor position in the table 60 can be investigated to provide values of the rotor angle corresponding to these values. If the winding resistance R is small, the iR term in Equation 1 can actually be ignored.
The slow mode utilizes a method of applying a diagnostic pulse to an inactive phase. When the pulse of the linkage flux reaches a predetermined value, the current is recorded and the phase is turned off. The position of the rotor can be read from the current table for the rotor angle with respect to this fixed magnetic flux. When the linkage flux is reduced to zero, the next pulse is started and the process is repeated. The repetition rate of the pulses is a choice for the system designer. That is, a pulse is applied at a fixed frequency and a new pulse can be started as soon as the measurement of the previous pulse is completed, and the circuit is ready to start a new measurement. Generally speaking, the linkage flux pulses have a peak value of about 5% to 10% of the peak linkage flux of the machine. In particular, if the value is small, there will be an error due to measurement noise. Larger values will result in acoustic noise and / or reduced output due to the negative torque generated. In addition, the larger the pulse, the longer it takes to reach the peak value, and the computation position becomes unclear. The peak chain flux value should be chosen to be appropriate for the environment. Note that, using a fixed current height pulse, it is possible to read the associated linkage flux to read the position from the position / linkage flux table.

For motoring operation, the pulse is located in the decreasing inductance region. For power generation operation, the pulses are placed in the rising inductance region. If the inductance profile of the machine is symmetrical, simply think about the maximum or minimum inductance angle and you will get the exact location for each mode, so you only need to store the current data for one set of locations. This system is shown schematically in FIG. 6, where LA, LB and LC represent the ideal inductance profiles of a three phase machine. Exc A, Exc B and Exc C represent the excitation angles for the motoring operation, and the region D represents the rotor angle in the range in which the phase can be diagnosed.

There is another way to calculate the linkage flux. The integral function given in Equation 1 accurately calculates the voltage drop across the switch and the voltage drop across the resistance of the winding. However, it is necessary to sense the voltage across both phase windings. In many applications, this method can be performed simply by integrating the DC link voltage by controlling the integrator by whether the switch is on, freewheel, or off. Although this method is less accurate than the method of Equation 1, this method requires only one voltage sensor, thus reducing the amount of hardware required.

The peak of the linkage flux pulse is preferably generated in region D shown in FIG. 6 for a predetermined machine speed. Of course, at rest, the pulse period is not a problem. However, as the speed increases, it must be taken into account that the same angle represented by the area D will correspond to a shorter time. Thus, if the peak value of the diagnostic pulse does not change with the machine speed, the peak value of the diagnostic pulse should be long enough to set the desired linkage flux level and short enough to be available even at the fastest machine speed. It is preferable that the time for applying two or more pulses to the area D is sufficient, so that several position measurements can be made in each diagnostic period. Examining a set of measurements can reduce the impact of a predetermined critical error, as described below. By measuring several times in the same diagnostic cycle, it is also possible to provide updated positional information that can be used for useful results, for example if the machine speed changes.

In contrast, fast mode examines the active phase and takes data from only one phase per inductance cycle. The reference point for the angle is already defined and the current and the linkage flux are measured at this reference point. Any error between the measured and anticipated linkage fluxes is used to derive the position error and derive a calibrated position estimate. This structure is shown schematically in FIG. 7 where LA, LB and LC represent the ideal inductance profiles of a three phase machine and Ref A, Ref B and Ref C represent the reference angles for the three phases in the motoring operation. . In the low speed mode, the motoring operation and the generating operation can be provided by utilizing the symmetry of the inductance profile.

In the low speed mode or the high speed mode, an estimate of the position may be used based on the calculation of speed and / or acceleration.

The low speed and high speed modes must have at least close start information about the rotor position for successful operation. In the low speed mode, a suitable area for application of the diagnostic pulse should be found, and in the high speed mode, the linkage flux and current measurement should be able to be obtained close enough to the reference angle with small position error. However, if the machine is at rest, the speed is not controlled, or if the load or control system is temporarily interrupted due to loss of position data, there is no approximate information about the position, and the system voluntarily resynchronizes. It is unlikely to be. Conventional control methods at low and high speeds have various problems in that they do not provide a reliable method of starting the machine, and also do not provide a method of restoring operation in the event of a loss of position detection. .

If there is no information about the rotor position and needs to start (or restart) the excitation of the winding, a diagnostic pulse can be applied to a phase such as, for example, phase A, as shown in FIG. However, the current and subsequent calculations, i.e. the measurement of A2, are unclear because they correspond to the position of A1. However, if simultaneous measurements of phase B are made, then positions B1 and B2 are found. Since a unique position must exist at either angle, it is accurate only at the two points to be matched (A2 and B1) and therefore the rotor position is determined. This is based on measurements made at the same time in practice, so it becomes important that any diagnostic pulses used have reached a predetermined value at substantially the same time. This condition is realized when a pulse of linkage flux is used. This is because the time required for winding to reach a predetermined linkage flux when driving from a substantially constant DC bus is effectively determined by the bus voltage when the phase is equal in number of turns and resistance. For this reason, the prior art using a fixed current value pulse is not suitable even if started at the same time, and an error occurs in position calculation because it reaches a predetermined value at different times.

The method of determining the rotor position is shown in the flow chart of FIG. 9 showing a portion of software in the ASIC.

In order to implement the method efficiently, the linkage flux in the phase must be started from zero because the integral process is initiated from the wrong starting point by some residual linkage flux. The program begins at block 70 indicating whether the machine has just been operated by accessing time from the most recent switch operation. If a sufficiently long period has elapsed since the most recent switching operation for the winding current (and the linkage flux) became zero, the program proceeds to block 72. If the elapsed time is not sufficient, a delay is performed in block 73 prior to block 72 to allow time for current and magnetic flux in the windings to be reduced.

In block 72, a diagnostic linkage flux pulse is applied to the two machine phases by operating the switch device properly. Pulses of a predetermined linkage flux are generated by the operation of the switch device so that the DC voltage is applied to the two windings simultaneously and during the same period. According to block 72, the current in the two-phase winding is detected by the current sensing element and converted at the end of the diagnostic pulse to a pair of digital values by the A / D converter 58 in the controller 54. The look-up table 60 of the controller 54 is accessed using the current value detected by the ASIC in block 74, so that the detected current value is for each monitored phase to be generated for the predetermined linkage flux pulse value, respectively. It provides two angular positions in the phase inductance cycle of. In order to make a storage space, it is possible to store only one angle value for each current value and use its symmetry characteristic to derive the other angles.

As mentioned above, there is a unique position corresponding to the combination of a pair of current values for each phase. Thus, while it is ambiguous to indicate which of the pair of angular positions is the current value of a single phase, combining the current values in the pair of phases will yield only one rotor angle that is substantially consistent. . The reason is that different current values will represent different positions in each rotor position cycle. Thus, the ASIC is programmed to compare the possible rotor angles and select the angle common to the current reading. Thus, the ASIC can be programmed in any one of several ways to accommodate angles close to each other in the tolerance level.

In block 75 the ASIC is programmed to determine an appropriate phase to excite based on the calculated rotor angle. The determination as to which phase to excite is based on the rotor pole position at the best torque generating position (in the desired direction of rotation) relative to one phase over the other phases. Based on this determination, an appropriate switch is operated at block 76 to apply the supply voltage V to the phase winding for excitation. The ASIC then transfers the normal control of the motor to other software routines in the ASIC at block 77. The rotor position is set by the present invention. Rotor position can be set even when the rotor is on or off as long as sufficient time has elapsed to reduce the current and magnetic flux of the winding to properly perform the correct reading to be taken in the monitored phase.

Sensorless position detection systems must be able to operate in electrically noisy environments close to power switching devices, such as where linkage flux and current measurements can be error prone and compute faulty position data. In order to improve the stability of the system, a method of validating the calculated position data has been developed. Each time a new position is computed, the position, time and velocity values can be stored. Using the last n stored values, the prediction position can be computed by extrapolation for comparison with the newly computed values. If the newly calculated and predicted value is not within the predetermined value, the error count is incremented and the predicted value is used instead of the calculated value. In addition, if the newly calculated predicted value is within the predetermined value, the error count is reduced and the calculated value is used. In the stationary state, the number of repetitions can be limited, but can still be used to check the rotor position.

In particular, in the case of regular operation in successive measurement cycles, the reliability of the position data is established. If the error count exceeds a predetermined value such as, for example, 5, the successive calculations do not match, the control system determines that it does not match the true position of the rotor to prevent the excitation of the machine before any serious event occurs. Or block). Storing and extrapolating the values can be done by any means, but is typically stored by digital storage. By setting the value of n to 8, it was found that a good balance between system stability and storage space was achieved.

This concept in the method according to the invention is performed by returning according to block 78 and repeating block 72 and block 74. As mentioned above, this iterative process can be realized not only when setting or resetting the rotor position but also in the rotor position diagnosis in a running machine.

Thus, it can be used to provide a series of n measurements based on checking the reliability of the (n + 1) th measurement before applying excitation to the phase. These measurements can be taken from continuous pulses.

The method according to the invention can be used whenever a loss of position data occurs, and the use of two phases for the diagnosis will be realized. When starting at zero speed or in operation, these conditions are achieved immediately. If a transient failure occurs in a load or control system where sudden loss of position data occurs, the condition may be performed by removing excitation from all (or at least two) phases and allowing sufficient time for the phase current to be reduced to zero. Can be. For example, the peak linkage flux can be estimated, and the time for the peak linkage flux to be reduced to zero can be estimated or the current can be monitored by the current transducer. Thus two phases can be diagnosed as mentioned above to generate the required position data, and appropriate excitation can be applied to the phases to generate the required torque in the required direction.

In addition, a system for checking the reliability of the data is used when the machine is in operation, as mentioned above, can be ignored when starting up, and a pair of measurements in two phases is performed as mentioned above. In addition, if the winding is in the freewheel state after reaching the required linkage flux, the continuous measurement can be taken from one extended pulse.

The above description is based on a system using a look-up table of rotor angles for current values. This is useful for digital implementation of control systems. However, the analog method of determining the position by applying the measured current value in a form representing the relationship between the current and the rotor angle when the linkage flux is used for diagnosis can also be used. This method would be desirable over look-up tables if digital storage is limited and generates high quantization errors that small tables cannot accommodate. Any analog representation can be used, for example, in November 1990, Proc IEE Pt B, Vol 137, NO 6, pp 337-347 by Miller et al, `` Nonlinear theory of the switched reluctance motor for Rapid Computer-aided Design , or Vol 3, pp 1674-1679 at ICEM'98 Internationan Conference on Electrical Machines, Istanbul, Turkey, September 2-4, 1998, by Piron. The application of magnetic gauge curves to linear motion solenoid actuators and rorary doubly salient reluctance machines .

Although the above embodiments are disclosed for a three phase machine, it will be appreciated that the present invention can be applied to a multiphase switched magnetoresistive machine having a predetermined number of poles. Likewise, the present invention can be applied to a linear machine in which a movable part (also called a "rotor") moves linearly. Accordingly, those skilled in the art will appreciate that variations of the disclosed constructions are possible without departing from the scope of the invention. Accordingly, the disclosed embodiments are shown by way of example and not by way of limitation. The invention will be limited only by the claims.

According to the present invention, the rotor position can be determined in a multiphase switched magnetoresistive machine having a rotor, a stator, and two or more excitable windings, which is stable and reliable, and a switched magnetoresistance that operates over the entire speed range of the machine A machine can be provided.

Claims (37)

A method of determining rotor position in a multiphase switched magnetoresistive machine comprising a rotor, a stator and two or more excitable phase windings, Applying a first diagnostic pulse of a predetermined flux linkage to a phase winding of one of the two or more excitable phase windings, Applying a second diagnostic pulse of a predetermined linkage flux to another of the two or more excitable phase windings simultaneously with the application of the first diagnostic pulse; Determining possible first rotor positions from the detected characteristic of the first diagnostic pulse; Determining possible second rotor positions from the detected characteristic of the second diagnostic pulse; Comparing the possible first rotor position with the second rotor position to resolve the ambiguity of the rotor positions. Rotor position determination method comprising a. The method of claim 1, wherein the detected characteristic of the first and second diagnostic pulses is a current in the phase winding. The method of claim 1, comprising storing in the look-up table pairs of possible rotor position values for each of a range of values of the detected characteristic of the first and second diagnostic pulses. Rotor position determination method. A motor according to claim 1 or 2, wherein a look-up table is provided for motoring and generating a single pair of values of rotor position for each of the values of the detected characteristic. The rotor position determining method. The method of claim 1 or 2, wherein the look-up table stores a single rotor position value for each of a range of values of characteristics detected from the first and second diagnostic pulses, And the rotor position determination method comprises inferring another value of the possible rotor positions using the symmetry of the magnetic properties of the switched magnetoresistive machine. 6. The method of claim 5, wherein the look-up table stores a single value of rotor positions for values of the detected characteristic as values for motoring and power generation. 3. The method of claim 1 or 2, wherein the step of resolving ambiguity is commonly shared by the detected characteristics by comparing possible rotor positions represented by the characteristics detected from the first and second diagnostic pulses. And selecting the indicated rotor position. The rotor position determination method according to claim 1 or 2, wherein the first and second diagnostic pulses are applied by driving of a switching means. The method of claim 1 or 2, wherein successive pairs of diagnostic pulses are applied at a fixed frequency. delete 3. The method of claim 1, wherein the first and second diagnostic pulses are applied only when the magnetic flux of each of the phase windings becomes zero. 4. 12. The method of claim 11, comprising delaying the application of the first and second diagnostic pulses so that magnetic flux can be attenuated to zero. 3. The method of claim 1, wherein the rotor position is checked by comparing a first determination of the rotor position with a second determination of at least the rotor position. 4. . The method of claim 13, wherein the multiphase switched magnetoresistive machine is driven or de-driven in accordance with the inspection of the rotor position. The rotor position determination method according to claim 1 or 2, wherein the determination of the rotor position is performed while the rotor is fixed. 3. The rotor position determination method according to claim 1 or 2, wherein the determination of the rotor position is made while the rotor is rotating. delete A machine having a rotor, stator, excitable windings having a plurality of phases, switch means operable to operate the plurality of phases, position detection means for inducing the position of the rotor relative to the stator, A switched magnetoresistive driver comprising means for driving said switch means in accordance with a rotor position, The position detecting means, Means for applying a first diagnostic pulse of a predetermined flux linkage to one of the plurality of phases, Means for applying a second diagnostic pulse of a predetermined linkage flux to another phase simultaneously with the application of the first diagnostic pulse; Means for determining a possible first rotor position from the characteristic of the first diagnostic pulse, and determining a possible second rotor position from the characteristic of the second diagnostic pulse; Means for resolving ambiguity in rotor position by analyzing the possible first and second rotor positions To include, the switched magnetoresistive driver. 19. The apparatus of claim 18, comprising at least one current monitor configured to detect the current in the phase windings, And wherein the detected characteristic of the first and second diagnostic pulses is a current. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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